The principle purpose of the project is to understand better the mechanism of DNA synthesis in normal and neoplastic cells. Current projects are primarily in two areas: 1. Clarification of the mechanism of initiation of new chains, specifically evidence on RNA priming. 2. Development of new systems for the study of DNA synthesis, in vitro; particularly utilizing parvovirus H-1 or LuIII infected HeLa cells; to identify components of the replication apparatus and their mechanism of action. BIBLIOGRAPHIC REFERENCES: Tseng, B. and Goulian, M.: DNA synthesis in human lymphocytes: Intermediates in DNA synthesis, in vitro and in vivo. J. Mol. Biol. 99: 317-337, 1975. Kiessling, A., and Goulian, M.: A comparison of the enzymatic responses of the DNA polymerases from four RNA tumor viruses. Biochem. Biophys. Res. Comm. 71: 1069-1077, 1976.